The present invention relates generally to an atherectomy device and method for reducing stenosis within vascular vessels.
Coronary and peripheral vascular arteriosclerosis, known also as atherosclerosis, is a common ailment occurring in humans which involves deposition of fatty-like substances called atheroma or plaque on the walls of blood vessels. These plaque deposits are most common in the peripheral blood vessels that feed the limbs of the human body and the coronary arteries which feed the heart. When long term plaque build-up reaches the point of nearly totally occluding a vessel, a thrombus (clot) type attachment can occur resulting in a long segment of soft vessel occlusion. Occasionally these fatty deposits occur in fairly localized regions of a blood vessel, thereby restricting the blood's flow and imposing a serious risk to the person's health.
In the past, several methods have been attempted to restore normal blood flow through the affected vessels. Traditionally, major surgery was the only practical means for treating occlusions. More recently, there has been substantial success in increasing the size of the flow passage within occluded vessels through the use of a dilation process known as balloon angioplasty. However, in a substantial percentage of the cases where balloon angioplasty is used, the removed plaque deposits will reoccur.
More recently, there has been an interest in atherectomy devices that actually cut through stenosis within a vessel regardless of whether the stenosis is primarily a plaque type deposit or a thrombus type clot. For example, U.S. Pat. No. 4,669,469 discloses a side cutting atherectomy device for removing material from an atheroma in the vascular system. Similarly, co-pending applications Ser. Nos. 045,916 filed May 1, 1987 and 117,072 filed Nov. 5, 1987, which are incorporated herein by reference, disclose alternative designs for end cutting atherectomy devices.
A drawback of such atherectomy devices is that they may leave rough edges when cutting. Additionally, since the cutter size is restricted, it is not always possible to open a passage as large as desired when using such devices. Further, such devices are not capable of securely anchoring the atherectomy device in place while cutting proceeds.
Another disadvantage of present devices is their inability to treat some occlusive complications, particularly those which arise during the periatherectomy period and require immediate attention. For example, diffuse or long atherosclerotic lesions are susceptible to abrupt closure (vessel occlusion) after angioplasty or atherectomy. This potentially fatal complication is best treated by successive dilation of the stenosis to re-establish perfusion to the heart muscle. To be successful, a balloon must be rapidly passed across the stenosis for redilation.
Thus, in some cases, it may be desirable or necessary to follow atherectomy with angioplasty. The use of a separate angioplasty balloon, however, results in significant delays in treatment. For example, time is lost in removing the atherectomy device, preparing the balloon for introduction, and accessing the lesion before performing the dilations. The removal of the atherectomy device may even cause the physician to lose access to the lesion altogether, thus preventing the later introduction of a balloon catheter. Since longer periods of vessel occlusion lead to increased heart muscle damage and worsening of eventual patient outcome, the desirability for immediate treatment is apparent.
What is needed is an atherectomy device with the added capability of promptly treating attendant complications, such as abrupt closure. The present invention fulfills this and other needs.